4206. In the event of a fire, the doors to a stair tower must be closed to prevent the spread of fire by which method?

Closing stair tower doors prevents fire spread by interrupting convection, the transfer of heat via rising hot gases and smoke. Conduction involves heat transfer through solids, while radiation involves electromagnetic waves; neither is primarily controlled by door closures. Ventilation is a firefighting tactic, not a method of heat transfer.